This invention relates to a marking apparatus for consecutively marking a plurality of packaged semiconductor devices.
In the commercial production of ICs and many other semiconductor devices the final step is making markings on each semiconductor device which is already packaged. It is prevailing to use a laser beam marker.
Packaged semiconductor devices are transferred to a feeding station precedent to a marking station usually by using tubular holders in each of which a plurality of semiconductor devices are received in a single file. In the case of a conventional marking apparatus, at the feeding station one of the tubular holders is set lengthwise at an end of a chute to release the semiconductor devices into the chute in a file. The chute extends to a turntable which is a part of the marking station. The turntable has a plurality of radially arranged receptacles each of which accepts one of the semiconductor devices transferred by the chute. The turntable stops rotating when any of the receptacles arrives at a marking position, and a laser beam is projected from a laser beam marker on the upside face of the semiconductor device held in that receptacle. By subsequent rotation of the turntable the receptacle holding the already marked semiconductor device comes into alignment with another chute which extends to a receiving station, and the semiconductor device is released into the chute as the turntable stops rotating. In the receiving station a plurality of marked semiconductor devices are put into a tubular holder in preparation for transfer to another station.
In the above described apparatus the dimensions of the tubular holders, chutes and the receptacles of the turntable correspond to the dimensions of a packaged semiconductor device of a specific kind. Therefore, when the object of marking is changed to another kind of semiconductor device there is the need of adjusting the tubular holder handling parts in the feeding and receiving stations, replacing some of such parts and replacing the chutes and the turntable. Usually it takes about 1 hr to accomplish such adjustment and replacement of parts. This is an obstacle to enhancement of a net working rate of the marking apparatus. Besides, the marking operation using the turntable cannot be regarded as sufficiently high in productivity in view of the fact that the operation time for each semiconductor device amounts to about 1.0 to 1.5 sec.